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authorAndreas Schwab <schwab@linux-m68k.org>2012-07-28 00:20:34 +0200
committerBen Hutchings <ben@decadent.org.uk>2012-08-10 00:25:13 +0100
commit56c5dc342e25deddf6fdfbed82a1b9d9bc118113 (patch)
tree909459d4467be481efa43353ae3cd81cf98aa0f7
parent922c97919db25e0950d180affa68d52af087a161 (diff)
m68k: Make sys_atomic_cmpxchg_32 work on classic m68k
commit 9e2760d18b3cf179534bbc27692c84879c61b97c upstream. User space access must always go through uaccess accessors, since on classic m68k user space and kernel space are completely separate. Signed-off-by: Andreas Schwab <schwab@linux-m68k.org> Tested-by: Thorsten Glaser <tg@debian.org> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r--arch/m68k/kernel/sys_m68k.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 8623f8dc16f8..9a5932ec3689 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -479,9 +479,13 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
goto bad_access;
}
- mem_value = *mem;
+ /*
+ * No need to check for EFAULT; we know that the page is
+ * present and writable.
+ */
+ __get_user(mem_value, mem);
if (mem_value == oldval)
- *mem = newval;
+ __put_user(newval, mem);
pte_unmap_unlock(pte, ptl);
up_read(&mm->mmap_sem);